The invention relates to a device for continuous production of expanded metal from metal foil.
Such a device is known from German patent document DE-38 14 448. In this device, an expansion unit comprises two pairs of toothed belts which grip both edges of a foil, and transport it longitudinally. A feed-surface body is arranged between the toothed belts in the form of a driven belt whose velocity is greater than or equal to the velocity of the winding foil.
Problems are associated with this unit with regard to obtainable quality, production speed, and energy consumption. Sufficient pressure and, consequently, sufficient traction cannot be placed on that stretch of the foil edges which is gripped by the two toothed belts so that during spreading by the feed-surface body, one edge or both edges can detach from the toothed belts. In addition, a spreading effect of the feed-surface body may be insufficient. This results in limitations in quality and production speed. Furthermore, overall friction forces which occur are substantial, resulting in significant energy requirements.
It is an object of this invention to improve the device of the type set forth above with regard to quality, production speed, and energy requirements.
This object is achieved according to this invention by the features set forth herein. Suitable enhancements of the invention are also set forth. A proposed embodiment makes possible a holding of a respective foil edge with required pressure between each toothed gear and a corresponding toothed belt in a region of a belt-wrap angle. This pressure can be adjusted in an uncomplicated manner. The feed-surface body advantageously is of several idling spread rollers arranged within the belt-wrap angle between the foil edges behind an entry point of the foil into the expansion unit. Using an expansion unit of the above type can reduce overall energy requirements to one-third.